From 6dba0d31ac07997867a8aa354695679d83f0e5f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Csik=C3=B3s=20Attila?= <zaeta17@gmail.com>
Date: Sun, 26 Nov 2023 22:42:54 +0100
Subject: [PATCH] Issue: #9 (KNN misses few neighborer nodes)

---
 octree.h                    | 12 +++++----
 unittests/general.tests.cpp | 50 +++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 5 deletions(-)

diff --git a/octree.h b/octree.h
index 29eea86..e438ef1 100644
--- a/octree.h
+++ b/octree.h
@@ -1753,7 +1753,7 @@ namespace OrthoTree
 
   private: // K Nearest Neighbor helpers
 
-    static geometry_type getBoxWallDistanceMax(vector_type const& pt, box_type const& box) noexcept
+    static geometry_type getBoxWallDistance(vector_type const& pt, box_type const& box) noexcept
     {
       autoc& ptMin = AD::box_min_c(box);
       autoc& ptMax = AD::box_max_c(box);
@@ -1771,7 +1771,7 @@ namespace OrthoTree
           return 0.0;
       }
 
-      return *std::min_element(begin(vDist), end(vDist));
+      return *std::ranges::min_element(vDist);
     }
 
 
@@ -1807,9 +1807,10 @@ namespace OrthoTree
       if (base::IsValidKey(kSmallestNode))
       {
         autoc& nodeSmallest = cont_at(this->m_nodes, kSmallestNode);
+        autoc wallDist = getBoxWallDistance(pt, nodeSmallest.box);
         createEntityDistance(nodeSmallest, pt, vpt, setEntity);
         if (!nodeSmallest.IsAnyChildExist())
-          if (getFarestDistance(setEntity, k) < getBoxWallDistanceMax(pt, nodeSmallest.box))
+          if (getFarestDistance(setEntity, k) < wallDist)
             return convertEntityDistanceToList(setEntity, k);
       }
 
@@ -1837,7 +1838,7 @@ namespace OrthoTree
 
       if (!setNodeDist.empty())
       {
-        auto rLatestNodeDist = std::begin(setNodeDist)->distance;
+        auto rLatestNodeDist = setEntity.size() > k ? next(setEntity.begin(), k)->distance : std::numeric_limits<geometry_type>::max();
         for (autoc& nodeDist : setNodeDist)
         {
           autoc n = setEntity.size();
@@ -1845,7 +1846,8 @@ namespace OrthoTree
             break;
 
           createEntityDistance(nodeDist.node, pt, vpt, setEntity);
-          rLatestNodeDist = nodeDist.distance;
+          if (setEntity.size() > k)
+            rLatestNodeDist = next(setEntity.begin(), k)->distance;
         }
       }
 
diff --git a/unittests/general.tests.cpp b/unittests/general.tests.cpp
index 734443d..34e669b 100644
--- a/unittests/general.tests.cpp
+++ b/unittests/general.tests.cpp
@@ -1709,6 +1709,56 @@ namespace Tree2DTest
       Assert::IsTrue(std::ranges::is_permutation(vector<size_t>{0, 1, 5, 6, 11}, vnn));
     }
 
+
+    TEST_METHOD(Issue9)
+    {
+      autoc poses = vector<array<double, 2>>
+      {
+        { 78.2619, 77.843 },
+        { 90.3005, 90.5172 },
+        { 69.8652, 12.2467 },
+        { 48.4675, 48.4948 },
+        { 36.3226, 68.4619 },
+        { 98.8799, 42.7149 },
+        { 31.412, 38.6866 },
+        { 63.2748, 77.0524 },
+        { 62.8844, 17.0536 },
+        { 80.8931, 39.8099 },
+        { 77.426, 64.9844 },
+        { 81.9552, 25.009 },
+        { 87.6088, 51.319 },
+        { 78.5609, 80.4623 },
+        { 51.3967, 39.5269 },
+        { 32.2042, 81.8779 },
+        { 79.1739, 81.5467 },
+        { 95.2619, 40.4742 },
+        { 86.437, 92.4406 },
+        { 3.95388, 60.2327 },
+        { 31.1283, 44.4917 },
+        { 35.6778, 79.8545 },
+        { 50.9926, 66.1373 },
+        { 3.16271, 65.2519 },
+        { 56.3665, 45.3819 }
+      };
+
+
+      autoce search_point = array<double, 2>{ 43.6406, 57.5691 };
+      using AD = OrthoTree::AdaptorGeneral<2, array<double, 2>, OrthoTree::BoundingBox2D>;
+      autoc itMin = std::ranges::min_element(poses, [&search_point](autoc& lhs, autoc& rhs) { return AD::distance2(lhs, search_point) < AD::distance2(rhs, search_point); });
+
+      std::array<double, 2> inspection_space_min = { 0.0, 0.0 };
+      std::array<double, 2> inspection_space_max = { 100.0, 100.0 };
+      OrthoTree::BoundingBox2D inspection_space;
+      inspection_space.Min = inspection_space_min;
+      inspection_space.Max = inspection_space_max;
+      //Standard Tree
+      auto tree = QuadtreePointC(poses, 9, inspection_space);
+
+      auto neighbors = tree.GetNearestNeighbors(search_point, 1);
+      Assert::AreEqual<size_t>(std::distance(poses.begin(), itMin), neighbors[0]);
+    }
+
+
   };
 
   TEST_CLASS(Box_General)